1. Field of the Invention
This invention relates to improvements in a piston of an internal combustion engine, and more particularly to a piston arranged to improve noise and vibration suppression characteristics of the engine.
2. Description of the Prior Art
A variety of pistons for an internal combustion engine have been proposed and put into practical use. Of these, a piston arrangement as shown in FIG. 3 of the drawings is known and disclosed in Japanese Utility Model Provisional Publication No. 62-8347. In this piston arrangement of FIG. 3, a piston skirt 2 of a piston body 1 is fixedly provided at its outer surface with a pad 3 which is high in wear resistance and oil keeping ability thereby improving a slidingly moving characteristics of the piston body 1 relative to a cylinder wall.
However, such a piston arrangement seems not to take account of thermal expansion and behavior of the piston during a reciprocating movement of the piston. More specifically, the pad 3 and the piston body 1 are different in thermal expansion, and therefore the pad 3 cannot follow the expansion of the piston body 1. In addition, the piston body 1 makes its generally arcuate oscillating movement around the axis of a piston pin during the reciprocating movement of the piston, so that the pad 3 cannot follow this oscillating movement of the piston body 1. These make difficult to control the posture of the piston body during engine operation, thereby sharply degrading noise and vibration suppression characteristics of the engine.